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Message-ID: <20250226010731.2456-3-chang.seok.bae@intel.com>
Date: Tue, 25 Feb 2025 17:07:22 -0800
From: "Chang S. Bae" <chang.seok.bae@...el.com>
To: linux-kernel@...r.kernel.org,
linux-kselftest@...r.kernel.org
Cc: x86@...nel.org,
tglx@...utronix.de,
mingo@...hat.com,
bp@...en8.de,
dave.hansen@...ux.intel.com,
shuah@...nel.org,
chang.seok.bae@...el.com
Subject: [PATCH 2/9] selftests/x86/xstate: Refactor XSAVE helpers for general use
The AMX test introduced several XSAVE-related helper functions, but so
far, it has been the only user of them. These helpers can be generalized
for broader test of multiple xstate features.
Move most XSAVE-related code into xsave.h, making it shareable. The
restructuring includes:
* Establishing low-level XSAVE helpers for saving and restoring register
states, as well as handling XSAVE buffers.
* Generalizing state data manipuldations: set_rand_data()
* Introducing a generic feature query helper: get_xstate_info()
While doing so, remove unused defines in amx.c.
Signed-off-by: Chang S. Bae <chang.seok.bae@...el.com>
---
tools/testing/selftests/x86/amx.c | 142 ++-------------------------
tools/testing/selftests/x86/xstate.h | 132 +++++++++++++++++++++++++
2 files changed, 142 insertions(+), 132 deletions(-)
create mode 100644 tools/testing/selftests/x86/xstate.h
diff --git a/tools/testing/selftests/x86/amx.c b/tools/testing/selftests/x86/amx.c
index 0f355f331f41..366cfec221e4 100644
--- a/tools/testing/selftests/x86/amx.c
+++ b/tools/testing/selftests/x86/amx.c
@@ -19,46 +19,13 @@
#include <sys/wait.h>
#include <sys/uio.h>
-#include "../kselftest.h" /* For __cpuid_count() */
#include "helpers.h"
+#include "xstate.h"
#ifndef __x86_64__
# error This test is 64-bit only
#endif
-#define XSAVE_HDR_OFFSET 512
-#define XSAVE_HDR_SIZE 64
-
-struct xsave_buffer {
- union {
- struct {
- char legacy[XSAVE_HDR_OFFSET];
- char header[XSAVE_HDR_SIZE];
- char extended[0];
- };
- char bytes[0];
- };
-};
-
-static inline void xsave(struct xsave_buffer *xbuf, uint64_t rfbm)
-{
- uint32_t rfbm_lo = rfbm;
- uint32_t rfbm_hi = rfbm >> 32;
-
- asm volatile("xsave (%%rdi)"
- : : "D" (xbuf), "a" (rfbm_lo), "d" (rfbm_hi)
- : "memory");
-}
-
-static inline void xrstor(struct xsave_buffer *xbuf, uint64_t rfbm)
-{
- uint32_t rfbm_lo = rfbm;
- uint32_t rfbm_hi = rfbm >> 32;
-
- asm volatile("xrstor (%%rdi)"
- : : "D" (xbuf), "a" (rfbm_lo), "d" (rfbm_hi));
-}
-
/* err() exits and will not return */
#define fatal_error(msg, ...) err(1, "[FAIL]\t" msg, ##__VA_ARGS__)
@@ -68,92 +35,12 @@ static inline void xrstor(struct xsave_buffer *xbuf, uint64_t rfbm)
#define XFEATURE_MASK_XTILEDATA (1 << XFEATURE_XTILEDATA)
#define XFEATURE_MASK_XTILE (XFEATURE_MASK_XTILECFG | XFEATURE_MASK_XTILEDATA)
-#define CPUID_LEAF1_ECX_XSAVE_MASK (1 << 26)
-#define CPUID_LEAF1_ECX_OSXSAVE_MASK (1 << 27)
-
static uint32_t xbuf_size;
-static struct {
- uint32_t xbuf_offset;
- uint32_t size;
-} xtiledata;
-
-#define CPUID_LEAF_XSTATE 0xd
-#define CPUID_SUBLEAF_XSTATE_USER 0x0
-#define TILE_CPUID 0x1d
-#define TILE_PALETTE_ID 0x1
-
-static void check_cpuid_xtiledata(void)
-{
- uint32_t eax, ebx, ecx, edx;
-
- __cpuid_count(CPUID_LEAF_XSTATE, CPUID_SUBLEAF_XSTATE_USER,
- eax, ebx, ecx, edx);
-
- /*
- * EBX enumerates the size (in bytes) required by the XSAVE
- * instruction for an XSAVE area containing all the user state
- * components corresponding to bits currently set in XCR0.
- *
- * Stash that off so it can be used to allocate buffers later.
- */
- xbuf_size = ebx;
-
- __cpuid_count(CPUID_LEAF_XSTATE, XFEATURE_XTILEDATA,
- eax, ebx, ecx, edx);
- /*
- * eax: XTILEDATA state component size
- * ebx: XTILEDATA state component offset in user buffer
- */
- if (!eax || !ebx)
- fatal_error("xstate cpuid: invalid tile data size/offset: %d/%d",
- eax, ebx);
-
- xtiledata.size = eax;
- xtiledata.xbuf_offset = ebx;
-}
+struct xstate_info xtiledata;
/* The helpers for managing XSAVE buffer and tile states: */
-struct xsave_buffer *alloc_xbuf(void)
-{
- struct xsave_buffer *xbuf;
-
- /* XSAVE buffer should be 64B-aligned. */
- xbuf = aligned_alloc(64, xbuf_size);
- if (!xbuf)
- fatal_error("aligned_alloc()");
- return xbuf;
-}
-
-static inline void clear_xstate_header(struct xsave_buffer *buffer)
-{
- memset(&buffer->header, 0, sizeof(buffer->header));
-}
-
-static inline void set_xstatebv(struct xsave_buffer *buffer, uint64_t bv)
-{
- /* XSTATE_BV is at the beginning of the header: */
- *(uint64_t *)(&buffer->header) = bv;
-}
-
-static void set_rand_tiledata(struct xsave_buffer *xbuf)
-{
- int *ptr = (int *)&xbuf->bytes[xtiledata.xbuf_offset];
- int data;
- int i;
-
- /*
- * Ensure that 'data' is never 0. This ensures that
- * the registers are never in their initial configuration
- * and thus never tracked as being in the init state.
- */
- data = rand() | 1;
-
- for (i = 0; i < xtiledata.size / sizeof(int); i++, ptr++)
- *ptr = data;
-}
-
struct xsave_buffer *stashed_xsave;
static void init_stashed_xsave(void)
@@ -169,21 +56,6 @@ static void free_stashed_xsave(void)
free(stashed_xsave);
}
-/* See 'struct _fpx_sw_bytes' at sigcontext.h */
-#define SW_BYTES_OFFSET 464
-/* N.B. The struct's field name varies so read from the offset. */
-#define SW_BYTES_BV_OFFSET (SW_BYTES_OFFSET + 8)
-
-static inline struct _fpx_sw_bytes *get_fpx_sw_bytes(void *buffer)
-{
- return (struct _fpx_sw_bytes *)(buffer + SW_BYTES_OFFSET);
-}
-
-static inline uint64_t get_fpx_sw_bytes_features(void *buffer)
-{
- return *(uint64_t *)(buffer + SW_BYTES_BV_OFFSET);
-}
-
/* Work around printf() being unsafe in signals: */
#define SIGNAL_BUF_LEN 1000
char signal_message_buffer[SIGNAL_BUF_LEN];
@@ -281,7 +153,7 @@ static inline bool load_rand_tiledata(struct xsave_buffer *xbuf)
{
clear_xstate_header(xbuf);
set_xstatebv(xbuf, XFEATURE_MASK_XTILEDATA);
- set_rand_tiledata(xbuf);
+ set_rand_data(&xtiledata, xbuf);
return xrstor_safe(xbuf, XFEATURE_MASK_XTILEDATA);
}
@@ -884,7 +756,13 @@ int main(void)
return KSFT_SKIP;
}
- check_cpuid_xtiledata();
+ xbuf_size = get_xbuf_size();
+
+ xtiledata = get_xstate_info(XFEATURE_XTILEDATA);
+ if (!xtiledata.size || !xtiledata.xbuf_offset) {
+ fatal_error("xstate cpuid: invalid tile data size/offset: %d/%d",
+ xtiledata.size, xtiledata.xbuf_offset);
+ }
init_stashed_xsave();
sethandler(SIGILL, handle_noperm, 0);
diff --git a/tools/testing/selftests/x86/xstate.h b/tools/testing/selftests/x86/xstate.h
new file mode 100644
index 000000000000..6729ffde6cc4
--- /dev/null
+++ b/tools/testing/selftests/x86/xstate.h
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#ifndef __SELFTESTS_X86_XSTATE_H
+#define __SELFTESTS_X86_XSTATE_H
+
+#include <stdint.h>
+
+#include "../kselftest.h"
+
+#define XSAVE_HDR_OFFSET 512
+#define XSAVE_HDR_SIZE 64
+
+struct xsave_buffer {
+ union {
+ struct {
+ char legacy[XSAVE_HDR_OFFSET];
+ char header[XSAVE_HDR_SIZE];
+ char extended[0];
+ };
+ char bytes[0];
+ };
+};
+
+static inline void xsave(struct xsave_buffer *xbuf, uint64_t rfbm)
+{
+ uint32_t rfbm_hi = rfbm >> 32;
+ uint32_t rfbm_lo = rfbm;
+
+ asm volatile("xsave (%%rdi)"
+ : : "D" (xbuf), "a" (rfbm_lo), "d" (rfbm_hi)
+ : "memory");
+}
+
+static inline void xrstor(struct xsave_buffer *xbuf, uint64_t rfbm)
+{
+ uint32_t rfbm_hi = rfbm >> 32;
+ uint32_t rfbm_lo = rfbm;
+
+ asm volatile("xrstor (%%rdi)"
+ : : "D" (xbuf), "a" (rfbm_lo), "d" (rfbm_hi));
+}
+
+#define CPUID_LEAF_XSTATE 0xd
+#define CPUID_SUBLEAF_XSTATE_USER 0x0
+
+static inline uint32_t get_xbuf_size(void)
+{
+ uint32_t eax, ebx, ecx, edx;
+
+ __cpuid_count(CPUID_LEAF_XSTATE, CPUID_SUBLEAF_XSTATE_USER,
+ eax, ebx, ecx, edx);
+
+ /*
+ * EBX enumerates the size (in bytes) required by the XSAVE
+ * instruction for an XSAVE area containing all the user state
+ * components corresponding to bits currently set in XCR0.
+ */
+ return ebx;
+}
+
+struct xstate_info {
+ uint32_t num;
+ uint32_t mask;
+ uint32_t xbuf_offset;
+ uint32_t size;
+};
+
+static inline struct xstate_info get_xstate_info(uint32_t xfeature_num)
+{
+ struct xstate_info xstate = { };
+ uint32_t eax, ebx, ecx, edx;
+
+ xstate.num = xfeature_num;
+ xstate.mask = 1 << xfeature_num;
+
+ __cpuid_count(CPUID_LEAF_XSTATE, xfeature_num,
+ eax, ebx, ecx, edx);
+ xstate.size = eax;
+ xstate.xbuf_offset = ebx;
+ return xstate;
+}
+
+static inline struct xsave_buffer *alloc_xbuf(void)
+{
+ uint32_t xbuf_size = get_xbuf_size();
+
+ /* XSAVE buffer should be 64B-aligned. */
+ return aligned_alloc(64, xbuf_size);
+}
+
+static inline void clear_xstate_header(struct xsave_buffer *xbuf)
+{
+ memset(&xbuf->header, 0, sizeof(xbuf->header));
+}
+
+static inline void set_xstatebv(struct xsave_buffer *xbuf, uint64_t bv)
+{
+ /* XSTATE_BV is at the beginning of the header: */
+ *(uint64_t *)(&xbuf->header) = bv;
+}
+
+/* See 'struct _fpx_sw_bytes' at sigcontext.h */
+#define SW_BYTES_OFFSET 464
+/* N.B. The struct's field name varies so read from the offset. */
+#define SW_BYTES_BV_OFFSET (SW_BYTES_OFFSET + 8)
+
+static inline struct _fpx_sw_bytes *get_fpx_sw_bytes(void *xbuf)
+{
+ return xbuf + SW_BYTES_OFFSET;
+}
+
+static inline uint64_t get_fpx_sw_bytes_features(void *buffer)
+{
+ return *(uint64_t *)(buffer + SW_BYTES_BV_OFFSET);
+}
+
+static inline void set_rand_data(struct xstate_info *xstate, struct xsave_buffer *xbuf)
+{
+ int *ptr = (int *)&xbuf->bytes[xstate->xbuf_offset];
+ int data, i;
+
+ /*
+ * Ensure that 'data' is never 0. This ensures that
+ * the registers are never in their initial configuration
+ * and thus never tracked as being in the init state.
+ */
+ data = rand() | 1;
+
+ for (i = 0; i < xstate->size / sizeof(int); i++, ptr++)
+ *ptr = data;
+}
+
+#endif /* __SELFTESTS_X86_XSTATE_H */
--
2.45.2
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